(1) Field of the Invention
The present invention relates to telephone answering systems and more particularly to systems employing call answering and recording equipment located remotely from the telephone subscriber's equipment.
(2) Description of the Prior Art
Equipment has frequently been provided in prior art telephone systems for automatically answering calls to customer stations when the called party is not available to do so. Such equipment is usually arranged to answer each call with a recorded announcement, to record any message from the caller and afterward to play back the recorded messages to the called customer. A variety of other features are also usually supplied by this equipment. For example, the customer generally is permitted to record and check his own answer announcement, and to repeat and skip certain passages during the playback period.
To provide these and other features present day equipment is usually located on the customer's premises. As a result installation and maintenance procedures are complicated because telephone company personnel must visit many locations to install and service equipment. In addition the customer desiring such answering service is presented with space problems in locating the additional equipment adjacent to a telephone. Obviously such conditions increase the cost of service. It has been suggested that in order to reduce the service cost and simplify installation and maintenance procedures, that the answering equipment be located at a telephone central office. While such arrangements overcome to some extent the foregoing objections, the provision of many features of answering service which are frequently requested by customers is not possible. For instance, the customer is unable to record his own answering announcement, instead he is required to use one prepared by the telephone company and he is given no control over the repeating or skipping of messages during playback. The service is further restricted when the customer can only obtain messages or playback at his own station.
Many of these objections have been overcome by a telephone answering system disclosed in U.S. Pat. No. 3,141,931 to Alfred Zarouni. However the Zarouni patent teaches that each customer who desires telephone answering service be assigned two line appearances in the switching network at the telephone central office. One of these lines is connected to the customer's answering equipment and with the line connected to the customer's station, it is used for ordinary telephone service. The other appearance is connected to the answering equipment by means of an answer and record line. This latter line is a so-called "unlisted" line, that is without a published directory number, and is used for allowing the customer to control his answering equipment.
It is obvious of course from the foregoing that the requirement for two telephone lines and the attendant disadvantages thereto are less than desirable. Such disadvantages include cost, service maintenance etc. as well as the possibility that if a person other than the customer subscribing to such service, discovers the unlisted number, he may be able to playback and monitor messages not intended for him. The system taught by Zarouni obviously lacks the privacy retaining features of prior art answering systems which were located on the customer's own premises.
Accordingly it is the principal object of the present invention to overcome the disadvantages of prior art telephone answering and recording systems and particularly to provide a telephone answering and recording system that may be located in a telephone central office or other centralized location which requires but a single telephone line between the customer's equipment and the centralized location for normal operation and accordingly provides the same privacy associated with such equipment when it is located at a customer controlled location.